Armytage has since condemned the article in an Instagram post, in which she labelled it “one of the most foolish opinion pieces I’ve ever encountered”.

“Attacking me for encouraging women to have mammograms. Honestly,” she wrote.

“At NO POINT did I give medical advice. My breast cancer specialist told me she would like women to be checked from 40 onwards.

“And all of my statistics for this story concerning breast cancer came from Breast Screen NSW.”

The TV personality’s on-air mammogram was part of a Sunrise series in which the show’s hosts, including David Koch, underwent life-saving medical tests.

During the segment, Meredith Kay from BreastScreen NSW informed Armytage the organisation urged women to have a mammogram every two years from the age of 50.

Sam Armytage at BreastScreen NSW. (Channel 7)

“But even at 40 it’s important for all women to know their breasts, isn’t it? Know what’s happening,” she responded.

“Absolutely. All women need to be aware of their breasts, particularly women of 40 but more, as we said, over 50,” Kay replied.

In her article, Dr Barratt said while screening women from 40 upwards may reduce the risk of breast cancer death in this age group “by a small amount”, the number of deaths avoided is “much less” than it is among older women.

The epidemiologist and professor of public health went on to explain that screening tests can lead to the “overdiagnosis” of slow-growing cancers that won’t result in symptoms or death, and are ultimately best left alone.

“The chance of having a false alarm ... and unnecessary biopsies, however, is higher for women in their 40s,” she wrote.

“Research shows the anxiety and emotional effects of health scares can be distressing and long lived.”

Dr Barratt said an “overdiagnosis” can also see women undergo treatments that are potentially harmful to them.

“Screening can turn healthy women of all ages into cancer patients who have surgery and drug and radiation treatments for a harmless cancer,” she wrote.

“It’s the poor balance of benefit to harm for women in their 40s that’s led to recommendations to start regular screening from 50 years, when the trade-off between risks and benefit becomes more favourable,” she concluded.

“With all this in mind, I urge women in their 40s to take a hard look at the latest research before following a celebrity’s well-meaning but uninformed advice.”

The BreastScreen NSW website states that women aged between 40 and 49 can come in for a screening mammogram, but advises the test is “less effective” for women in that age group.

“You can speak to your GP about whether breast screening is right for you,” the site adds.